This invention relates to bis(N,N-dihydrocarbylamino)-substituted derivatives of cyclopentadienes (Cp) and metal complexes thereof which find utility as olefin polymerization catalyst components.
Constrained geometry complexes (CGC) and methods for their preparation are disclosed in U.S. Pat. Nos. 5,703,187, 5,064,802, 5,055,438, 5,057,475, 5,096,867, 5,064,802, 5,132,380, as well as EP-A-514,828, WO 95/00526, and elsewhere. EP-A-577,581 discloses unsymmetrical bis-Cp metallocenes containing a fluorenyl ligand with heteroatom substituents.
E. Barsties; S. Schaible; M.-H. Prosenc; U. Rief; W. Roll; O. Weyland; B. Dorerer; H.-H. Brintzinger, J. Organometallic Chem. 1996, 520, 63-68, and H. Plenio; D. Birth, J. Organometallic Chem. 1996, 519, 269-272 disclose non-bridged and Si-bridged ansa bis-indenyl complexes in which the 5 membered ring of the indenyl group is substituted with a dimethylamino substituent. The complexes were disclosed as useful components of catalysts for use in the formation of polyethylene and isotactic polypropylene.
Disclosure of random heteroatom substitution in mono-Cp metallocenes is found in EP-A-416,815, WO 95/07942, WO 96/13529, and U.S. Pat. Nos. 5,096,867 and 5,621,126. Specific heteroatom substitution of the 3- and 2-position of indenyl complexes of group 4 metals was disclosed in WO98/06727 and WO/98/06728 respectively. The foregoing specifically substituted metal complexes have produced improved catalyst results, however, problems still remain with catalyst efficiency and deactivation of the catalyst under high temperature polymerization conditions. It would be advantageous to be able to produce polyolefins with higher molecular weights. It would also be advantageous to be able to improve other physical characteristics of the polymers produced by altering the substitution around the cyclopentadienyl group of the metallocene complexes used in olefin polymerization catalyst systems.